These are chat archives for thunder-project/thunder

28th
Jan 2015
Davis Bennett
@d-v-b
Jan 28 2015 04:16
i'm very excited about meanOfregion
Jeremy Freeman
@freeman-lab
Jan 28 2015 04:58
me too, @industrial-sloth nailed it... just merged into master
Jeremy Freeman
@freeman-lab
Jan 28 2015 05:32
just testing it alongside the new lightning code, working really nicely... only glitch is that the get_coords should probably allow an optional argument z
right now, regions are drawn in 2D, but if that 2D image corresponds to some z-index, you want to embed that in the keys
before calling meanByRegion
i can make the change @d-v-b if that sounds reasonable
Davis Bennett
@d-v-b
Jan 28 2015 06:10
yeah that makes a lot of sense
Jeremy Freeman
@freeman-lab
Jan 28 2015 06:10
eventually the gallery or similar type will handle multiple planes
but that's a topic for the lightning gitter
Davis Bennett
@d-v-b
Jan 28 2015 06:11
I looked at the way meanByRegion is implemented, and it seems like it would not be simple to have xByRegion where x is some function like Stdev
Jeremy Freeman
@freeman-lab
Jan 28 2015 06:12
yeah @industrial-sloth and I discussed this
Davis Bennett
@d-v-b
Jan 28 2015 06:12
but generally, if I'm taking an average, it can be nice to have a measure of std at least
ultimately this might be a job for an indexable rdd
Jeremy Freeman
@freeman-lab
Jan 28 2015 06:12
we might be able to extend at least with stdev, but supporting arbitrary aggregations here is tricky
well, not really
Davis Bennett
@d-v-b
Jan 28 2015 06:14
why are arbitrary aggregations hard?
Jeremy Freeman
@freeman-lab
Jan 28 2015 06:14
it's just the fact that to do an aggregation efficiently, you want to use a commutative and associative reduce function, as opposed to grouping all elements together and then calling your aggregation function
Davis Bennett
@d-v-b
Jan 28 2015 06:14
aha
Jeremy Freeman
@freeman-lab
Jan 28 2015 06:15
sum, max, etc. are simple reduce functions, mean takes more care, and a little more care for stdev
but the point is that beyond simple functions they require special handling
so we couldn't write a generic function for all of them
we can try to at least add stdev
Davis Bennett
@d-v-b
Jan 28 2015 06:15
well mean is a good start at least!
Jeremy Freeman
@freeman-lab
Jan 28 2015 06:15
yup!
Davis Bennett
@d-v-b
Jan 28 2015 06:15
i'm looking forward to using it